Avalonia/samples/ControlCatalog/Pages/NavigationPage/NavigationPageBackButtonPage.xaml

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             x:Class="ControlCatalog.Pages.NavigationPageBackButtonPage">
  <DockPanel>
    <ScrollViewer DockPanel.Dock="Right" Width="280">
      <StackPanel Margin="12" Spacing="14">
        <TextBlock Text="Configuration" FontSize="16" FontWeight="SemiBold"
                   Foreground="{DynamicResource SystemControlHighlightAccentBrush}" />

        <!-- Global override -->
        <TextBlock Text="Global Override" FontSize="13" FontWeight="SemiBold" />
        <TextBlock Text="IsBackButtonVisible=false hides the back button for every page in this NavigationPage."
                   TextWrapping="Wrap" FontSize="11" Opacity="0.6" />
        <CheckBox x:Name="IsBackButtonVisibleCheck" Content="IsBackButtonVisible"
                  IsChecked="True" IsCheckedChanged="OnGlobalBackButtonChanged" />

        <Separator />

        <!-- Per-page visibility -->
        <TextBlock Text="Per-Page Visibility" FontSize="13" FontWeight="SemiBold" />
        <StackPanel Spacing="6">
          <Button Content="Standard Page" Click="OnPushStandard"
                  HorizontalAlignment="Stretch" />
          <Button Content="Hidden Back Button" Click="OnPushNoBack"
                  HorizontalAlignment="Stretch" />
        </StackPanel>

        <Separator />

        <!-- Per-page enabled/disabled -->
        <TextBlock Text="Per-Page Enabled" FontSize="13" FontWeight="SemiBold" />
        <TextBlock Text="IsBackButtonEnabled=false shows the back button grayed out and non-interactive."
                   TextWrapping="Wrap" FontSize="11" Opacity="0.6" />
        <Button Content="Disabled Back Button" Click="OnPushDisabledBack"
                HorizontalAlignment="Stretch" />

        <Separator />

        <!-- Custom BackButtonContent -->
        <TextBlock Text="Custom Back Content" FontSize="13" FontWeight="SemiBold" />
        <TextBlock Text="Any string, icon or control can be the back button content."
                   TextWrapping="Wrap" FontSize="11" Opacity="0.6" />
        <TextBox x:Name="BackContentInput" PlaceholderText="Text content (default: Cancel)..." />
        <StackPanel Spacing="6">
          <Button Content="Push with Text Content" Click="OnPushCustomText"
                  HorizontalAlignment="Stretch" />
          <Button Content="Push with Icon (×)" Click="OnPushCustomIcon"
                  HorizontalAlignment="Stretch" />
          <Button Content="Push with Icon + Text" Click="OnPushIconTextBack"
                  HorizontalAlignment="Stretch" />
        </StackPanel>

        <Separator />

        <!-- Navigation Guard -->
        <TextBlock Text="Navigation Guard" FontSize="13" FontWeight="SemiBold" />
        <TextBlock Text="Push a page that intercepts back navigation."
                   TextWrapping="Wrap" FontSize="11" Opacity="0.6" />
        <StackPanel Spacing="6">
          <RadioButton x:Name="CancelRadio" GroupName="GuardMode"
                       Content="Cancel navigation" IsChecked="True" />
          <RadioButton x:Name="DeferRadio" GroupName="GuardMode"
                       Content="Async save (1.5s)" />
        </StackPanel>
        <Button Content="Push Guarded Page" Click="OnPushGuarded"
                HorizontalAlignment="Stretch" />

        <Separator />
        <TextBlock Text="Navigation" FontSize="13" FontWeight="SemiBold" />
        <StackPanel Spacing="6">
          <Button Content="Pop" Click="OnPop" HorizontalAlignment="Stretch" />
          <Button Content="Pop to Root" Click="OnPopToRoot" HorizontalAlignment="Stretch" />
        </StackPanel>

        <Separator />

        <!-- Event Log -->
        <DockPanel>
          <TextBlock DockPanel.Dock="Left" Text="Event Log" FontSize="13" FontWeight="SemiBold"
                     VerticalAlignment="Center" />
          <Button DockPanel.Dock="Right" Content="Clear" Click="OnClearLog"
                  HorizontalAlignment="Right" Padding="8,2" FontSize="11" />
        </DockPanel>
        <Border Background="{DynamicResource SystemControlBackgroundBaseLowBrush}"
                CornerRadius="4" Padding="8" MinHeight="100" MaxHeight="200">
          <ScrollViewer>
            <StackPanel x:Name="LogPanel" Spacing="1" />
          </ScrollViewer>
        </Border>

      </StackPanel>
    </ScrollViewer>

    <Border DockPanel.Dock="Right" Width="1" Background="{DynamicResource SystemControlForegroundBaseMediumLowBrush}" />

    <Border Margin="12"
            BorderBrush="{DynamicResource SystemControlForegroundBaseMediumLowBrush}"
            BorderThickness="1"
            CornerRadius="6"
            ClipToBounds="True">
      <NavigationPage x:Name="DemoNav" />
    </Border>
  </DockPanel>
</UserControl>